Die sets for machine presses



Feb. 18, 1958 w. J. BLAZEK ETAL DIE SETS FOR MACHINE PRESSES 2Sheets-Sheet 1 Filed Aug. 26, 1955 INVENTORS Feb. 18,1958 w. J. BLAZEKEm 2, 23,960

DIE SETS FOR MACHINE PRESSES- Filed Aug. 26, 1955 2 Sheets-Sheet 2mvsmoas WJBZaze/c JJ Sfrnad ATTORNEY United States Patent DIE SETS FORMACHINE PRESSES William J. Blazek, New Lexington, and James J. Strnad,Bedford, Ohio, assignors, by mesne assignments, to Ltemfilco Products,Inc., Bedford, Ohio, a corporation 0 O 'o Application August 26, 1955,Serial No. 530,857 9 Claims. (Cl. 308--6) This invention relates toguiding appliances, such as those used on machine tools for maintainingregistry between relatively movable parts. More specifically, thisinvention is concerned with punch press die sets of the type in which abed or bolster-carried die holder and a movable ram mounted punch holderare maintained in all positions of press operation in true relativealignment. Die sets of this general character are disclosed in the priorpatent of Conner, No. 2,422,775, granted June 24, 1947.

As set forth in the above patent, such a die set may comprise an upperpunch holder and a lower bed or bolstermounted die holder. The upperholder is securely attached to and movable in unison with the slide orram of an associated punch press, while the die holder is adapted forattachment to the stationary bed or bolster of a press. The upper holdercarries the punch or upper section of a given die assembly while thelower holder carries normally the stationary die section of saidassembly.

To maintain true alignment of the holders and die sections carriedthereby, the lower bed or bolster-mounted holder has mounted thereon aplurality of fixed, relatively spaced, hollow, upright guide members,known as bushing's. The associated punch holder carries in axialregistry with each of said bushings a rigid, depending, guide post orpin. Each bushing includes a relatively enlarged internal chamber, andbetween the spaced wall surface of each of these chambers and themovable post entering the same, antifriction bearing devices areinterposed. Each of these devices includes a plurality of rollingelements having simultaneous pressure contact with spaced wall surfacesprovided between the posts and bushings, whereby to provide for relativelongitudinal and axial movement but precluding lateral movement of theposts.

In general, such guide appliances have been formed to include two types.The first of these is a general commercially employed type in which theguide pins or posts, the antifriction ball-bearing retainers and thebushings are round or circular in their transverse cross sections, asshown in the above Patent No. 2,422,774. in a second type, each pin orpost, the bearing retainer and the receiving chamber therefor providedin each bushing is substantially square, or of other polygonaltransverse configuration. When the flat-sided polygonal type of pin orpost is provided, use is made in connection therewith of elongatedroller hearings in each retainer cage or frame in lieu of the ballbearings employed in the round or circular pin or post construction.Both forms have certain individual advantages. The cross-sectionallyround or circular pin, with correspondingly formed associated parts,enablesthe parts to be accurately machined and finished to closedimensional tolerances, which latter in a practical sense are ditficultif not impossible to obtain from a manufacturing and cost standpointwhen the polygonal type of pin and its associated parts are used.

However, the round pin requires the use of a correspondingly formedbearing retainer, necessitating the use Of ball-bearing a'ntifrictionelements with their limited surface area of contact while under pressureloading between associated cylindrical pin and bushing surfaces; a

condition which is apt to cause undesirable pitting and scoring of ballelement-engaged surfaces. Withthe use of the square, or other polygonal,type of pin, the antifriction elements possess the form of elongatedcylindrical rollers, having greatly extended areas of surface contact incomparison with ball-type elements. The roller type of antifrictionbearing is used between flat, opposed, wall surfaces of a cooperativepost and bushing, with the result that less Wear is present and pittingand scoring is prevented or minimized. Also, in this construction animproved stable, guiding action is obtained. However,

because of the practical difficulties in machining truly flat;

surfaces disposed in proper geometric relation to each other on theposts and bushings for bearing contact, the square or polygonal pin hasnot been deemed suitable for commercial employment in obtaining accuratesurface;

control, and its use has been accordingly restricted.

It is an object of the present invention, therefore, toprovide die setguides of the polygonal type which are so constructed and arranged as tocompensate for any absence in the true flatness or parallelism withpost, axes, of its bearing-engaging surfaces, this being accomplishedwithout sacrificing the accuracy thereof of the structurein the guidanceof associated relatively movable die set parts, or in causing anyshortening of the period of operating usefulness normally expected fromguides of this type. r

Another object is to provide a die set in which the bush-. ing-receivedposts thereof present a multiplicity of sub stantially flat surfacesdisposed for engagement with roller? or other bearings retained forfloating movement in bush-.

ing chambers having flat surfaces complemental to those of the posts,and wherein the construction is such that each complemental pair of saidsurfaces is yieldable under normal operating conditions of the die set,whereby to. compensate for unevenness, or the absence of true parallelism in the roller-engaged regions of said surfaces. 3

A further object of the invention is toprovide a fiatsurfaced,substantially square guide post or pin for punch press die sets whereinthe body of the guide post is slotted adjacent to the flat outer regionsthereof in a manner admitting of limited resilient, inward displacementof one or more of such regions in response to roller-bearing.

pressures applied to uneven areas of said surfaces, such displacementbeing effected as the pin or post reciprocates" in a bushing in whichassociated roller-bearing means are mounted.

An additional object is to provide an alternate form of die set guidemeans wherein a fiat-surfaced guide pin or post, substantially polygonalin its cross section and movable with the sliding head of a punch press,has its lower portion received in a chamber provided therefor in astationary bed or bolster-mounted bushing, and wherein parallel, segmentmembers are provided in said chamber and disposed between the wallsthereof and frame-retained roller bearings surrounding the movable lowerend of the pin or post, said segment members being constructed to yieldresiliently and radially of the guide means in com.-

. ,pensating for surface irregularitiescausing an absence of perfectplane conditions in the flat bearing-contacting surfaces of the pin orpost. i A still further object is to improve generally the constructionof die set guides employing antifriction bearings. For a furtherunderstanding ofthe invention, including additional objects andadvantages thereof, reference may now be had to the followingdescription'and accompany-s ing drawings, wherein:

Fig. l is a view partly in front elevation and in vertical 1 Pa itentedFeb. 18,

section of a punch press die set formed with the guide means of thepresent invention;

Fig. 2 is a detail horizontal sectional view taken on the planeindicated by the line 2-2 of Fig. 1;

Fig. 3 is a vertical sectional view on the line 3 -3 of Fig. 1;.

Fig. 4 is a similar view disclosing a variation of the slotted pin orpost of Fig. 2;

Fig. 5'is also a similar cross-sectional view disclosing a form of theinvention in which radially slotted segments are stationarily formed inthe bushing element of the guide assembly;

Fig. 6 is a similar view disclosing modified gib inserts which areinteriorly slotted for limited yieldability;

Pg. 7 is a similar horizontal sectional view in which solid gib insertsare formed with convex outer surfaces of greater or flatter curvaturethan that of the contacting inner walls of the associated bushing toyieldably space the inserts from said walls;

Fig. 8'i's a variation of the construction of Fig. 7 wherein the convexouter surfaces of the sectional and solid gib inserts possess acurvature based on arcs of shorter radii than that of the contactingbushing wall;

Fig. 9 is a horizontal sectional view, disclosing a modification inwhich gib inserts are disposed between the pin or post of the guideassembly and the antifriction bearing means;

Figs. 10 and 11 are detail cross-sectional views of still furthermodified forms of the invention.

The present invention, as above set forth, aims to provide certainimprovements in die sets having square pin and bushing constructionssuch as those disclosed in the Conner patent, No. 2,422,775, supra,particularly in the matter of compensating for the absence of true,flat, bearing-contacting surfaces between the pins and bushings, sincesuch surfaces often are found to be out of parallelism with the postaxis or proper geometrical relation to each other.

Therefore, the present invention provides means to maintain alignmentbetween members which are movable toward and away from each other, thesame being in the form of guide means carried by the other member andwith meansinterposed between the guide means to decrease frictionalresistance and control relative lateral movement therebetween. The guidemeans are preferably provided with flat angularly related bearingsurfaces and the antifriction means interposed between such surfaces arepreferably in the form of roller bearings. The space present between therelatively movable members may be such that the bearingshave arelatively close fit therein, limiting the amount of any lateral motiontherebetween. In the preferred arrangement, the space between the guidemembers is such that the rolling bearing elements are confined thereinunder pressure. This pressure, as defined in said Conner patent, mayvary between relatively wide limits from a point where the pressure isvery light to that where it is quite heavy. In some instances it may bedesirable that no pre-loading of the hearing be provided, but inmost'applications the pro-loading is such that the bearing elements willmove concomitantly with the associated movable member but at a higherrate of linear travel.

Referring now to the drawings, and to the specific form of'the presentinvention illustrated in Figs. 1' through 3 thereof, the die setillustrated is shown as including a fiat upper plate or punch holder 1which is provided centrally with an upright stem 2, the latter enablingthe plate to be secured to the traveling head or slide of a press, notshown, in a well-known manner. Cooperative with the plate 1 isa spaced,parallel, bottom plate or die holder 3 which may be bolted, or otherwiseconventionally secured, to an associated press bed or bolster B.

In this instance, the plate 1 has beenshown as being provided at the endthereof with vertical openings 4 in which are tightly fitted theshouldered upper ends of a pair of rigidly depending leader pins orposts 5, the latter extending downwardly from the plate 3. in spacedparallel order toward the bottom plate 3. These pins or posts arepreferably square or polygonal in cross section, presenting amultiplicity of angularly disposed flat surfaces 6, the presentinvention being concerned primarily with the provision of meanscompensating for the absence of true flatness and relativeperpendicularity of these surfaces and in producing as a result of theconstruction uniform functioning of die sets containing such leader pinsor posts.

Cooperating with said pins or posts 5 are stationary hollow guides,ordinarily referred to as bushings, and which are indicated at I in thedrawings. These bushings are formed with shouldered and reduced lowerends 8 which are positioned in and maintained in tight contact with thewall surfaces of a pair of openings formed in the lower or bottom plate3, the bushings being disposed in axial alignment with the pins 5.

In the form of the invention disclosed in Figs. 1 through 3, thebushings are provided with internal bores or chambers 9, the latterbeing substantially square in cross section to conform with theconfiguration of the pins or posts 5. However, the pins or posts aresufiiciently smaller in their cross sectional dimensions than saidchambers 9 so that the flat wall surfaces 10 of the chambers will bespaced from the outer complemental surfaces 6 of the pins or posts todefine rectangular bearing-receiving spaces 11 therebetween.

The bearing assembly 12, which is received in these spaces, is of suchsize that the roller bearing elements 12a thereof will span the spaces11 present between the pins or posts 5 and the walls of the bushings 7.Preferably the bearing elements 12a should be of such size that theyprevent lateral movement between the pins or posts and the guidebushings. This condition is known as loading or pre-loading and theamount thereof may be varied. The bearing elements 12a are preferably ofthe elongated roller type, the same being supported in a confiningretainer frame or cage structure 13 in spaced, parallel, vertical rowswith each bearing element arranged for rotation about its long axis.While ball bearings may also be used, it is advantageous to employroller bearing elements because of their extended line contact with theassociated fiat pin and bearing surfaces. The hearing assembly whenpro-loaded moves with the pins or posts as the latter reciprocatevertically, but at a lower rate of linear travel, the assembly beingsustained in spaced elevated relation with respect to the bottoms of thebushings by the loading pressures applied to the roller elements thereofby the opposed fiat wall surfaces of the pins and bushings and whichexert squeezing forces on the roller elements. 7

In accordance with the present invention, one of its novel anddistinguishing features resides in providing each of the pins or postswith corner-intersecting, radially disposed, vertical slots, asindicated at 14 in Fig. 2. It will be observed by reference to thisfigure that the slots open to the vertical corner edges of each pin orpost and that the closed inner ends of the slots terminate in the centeror axial regions of said pins or posts. By so slotting the pins orposts, each of the latter presents a plurality of outer bearingsurface-containing regions or segments 15 which under predeterminedpressures are inwardly and resiliently yieldable to an extent adequateto compensate for the minute surface irregularities or imperfectionswhich'may be present in the flat bearing faces or surfaces 6 of the pinsor posts 5 or 10 of the bushings 7. As stated, these surfaceimperfections or irregularities when present constitute but slight departures from theoretically perfect planes, and appear usually in but asmall localized area or areas of a given surface. Therefore, the slightdegree of yieldability of the regions 15 of the pins or posts, asafforded by the slots 14, will not in any way interfere with the fullyguided control and alignment of the relatively separable die section'scarried by the plates 1 and 3, but will greatly reduce the amount ofwear between the bearings, posts and bushings.

This feature of limited yieldability may, of course, be incorporated inthe die set in different ways, as, among others, those specificallyillustrated in Figs. 4 through 9 of the drawings.

The pin or post disclosed in Fig. 4 is provided with a plurality ofslots 16, which in the main extend parallel with the surfaces 6, butwith the open end of each slot opening to a surface 6 with respect towhich the slot extends at right angles. The outer fiatsurface-containing regions or segments 15 produced by this arrangementof slots possesses all yieldability necessary for the overcoming ofsurface imperfections above noted.

In the form of the invention illustrated in Fig. 5, radial or otherslots 17 are formed in a plurality of stationary inserts or segments 18integrally formed with or carried by the bushing 7. These inserts areformed with flat bearing surfaces 19 disposed in opposed but spacedrelation to the surfaces '6 of a pin or post 5. In this instance, thepin or post has been shown as being cross-sectionally solid and devoidof the slots of Fig. 2. However, a slotted pin or post may be used inconjunction With the inserts or segments 18 if desired. The usual rollerbearing assembly 12 is mounted in the restricted rectangular space 11formed between the surfaces 6 and 19, the roller bearing elements 12a ofthe assembly engaging the opposed surfaces under pre-load confiningpressures.

Fig. 6 sets forth substantially the same arrangement as in Fig. 5, butin Fig. 6 the bushing segments 18 are each provided with a plurality ofparallel slots 20 which are spaced from each other and occupy a parallelrelation with respect to bearing surfaces 19.

In lieu of slotting the bushing segments or the leader pins or posts asheretofore defined in obtaining bearing element relief by preventingoverloading thereof, as caused by passing the same through excessivelyrestricted operating spaces 11, the present invention may employ thesolid segments 21 and 21a of Figs. 7 and 8, respectively. These segmentsare in the form of inserts and, as shown, are separate from the bushings7a and from each other. The distinguishing feature of the segments 21 ofFig. 7 is to be found in the curvature of the convex outer surfaces 22thereof. It will be noted that the surface 22 of each segment 21possesses a convex curvature forming a segment of a circle having agreater diameter than the circle of curvature of the inner cylindricalsurface of the associated bushing 7a. As a result of these differencesin curvature, a thin crescent-shaped space 23 is defined between theouter convex segment surface 22 and the associated cylindrical bushingwall, with the spaced, outer longitudinal edge 24 of each segment 21disposed in contact with the inner wall of the bushing. The spaces 23are so formed and disposed as to admit of resilient yielding thereof inan outward and radial direction. This action takes place, as previouslyexplained, when bearing overloading is effected as a result ofirregularities in the flat surfaces 25 of the segments, or the surfaces6 of the pins, producing undesired overloading of the roller elements12a of the bearing assembly.

In the construction of Fig. 8, the segments 21a have convex outersurfaces 22a, the central portions only of which bear on the cylindricalwall of the bore or chamber 9 of the bushing 7a, as contrasted with thedual bearing edges 24 of the segments 21. Such centralized contact ofthe segments 21a with the bushing 7a is attributable to the fact thateach surface 22a constitutes a segment of a circle having a smallerdiameter than the circular bore of the associated bushing 7a.

A further variation is set forth in Fig. 9 wherein the inserts orsegments 26 are disposed between the pins or posts and the rollerbearing assembly 12, the roller elements 12a of the assembly beingdisposed in preloaded, simultaneous contact with the rectangularly ar-Fig. 10, the post 5b and the retainer 712 are of triangular.

configuration. Other such variations are, of course, possible.

We claim:

1. A die set comprising relatively movable, spaced and interfitting postand bushing members adapted for straight line motion and which aresubstantially polygonal in cross section in providing substantiallyflat, opposing and relatively spaced surfaces; a retainer structureconforming to the polygonal cross-sectional configuration of the spaceformed between said members, said structure including a plurality ofindependently movable bearing elements having simultaneous preloadedpressure contact.

with said opposing surfaces; and resilient means incorporated in atleast one of said members and providing yielding displacement thereof inresponse to abnormal pressures applied to the bearing elements uponpassing of the latter between portions of said opposing surfaces whichare out of true geometrical relation to each other and in parallelismwith post axes.

2. A guide post for die sets comprising: an integral, elongated,polygonal body, including a plurality of recessseparated, outwardlydisposed bearing regions and a solid core region; each of said bearingregions presenting a longitudinally elongated, flat, outer surface, therecesses separating said bearing regions serving to admit of inwardyielding movement of the latter in response to abnormal inwardlydirected forces applied to said surfaces.

3. A guide post for die sets as defined in claim 2, and wherein saidrecesses extend substantially inwardly of said body and open at theirouter ends to corner regions of said body defining said surfaces.

4. A guide post for die sets comprising: an elongated body substantiallysquare in cross section and formed with flat bearing faces on the outersides thereof, said body including a central longitudinal core regionintegrally joined with relatively movable outer regions on which saidbearing faces are formed, said outer regions including merging webportions of narrow Width with respect to the width of one of said faces.

5. A die set comprising relatively movable, spaced and interfitting postand bushing members adapted for straight line motion and which aresubstantially polygonal in cross section in providing substantiallyflat, opposing and relatively spaced surfaces; a retainer structureconforming to the polygonal cross-sectional configuration of the spaceformed between said members, said structure including a plurality ofindependently movable bearing elements having simultaneous preloadedpressure contact with said opposing surfaces; and resilient meansincorporated in said post member and providing yielding displacementthereof in response to abnormal pressures applied to the bearingelements upon passing of the latter between portions of said opposingsurfaces which are out of true geometrical relation to each other and inparallelism with post axes.

6. In a die set; a pair of relatively interfitting and linearlyreciprocable members each provided with opposing, relatively spaced,substantially parallel flat surfaces defining therebetween a chamber ofpolygonal cross-sectional configuration; a bearing retainer conforminggenerally to the polygonal cross-sectional configuration of said chamberand positioned in said chamber for longitudinal reciprocating movementtherein, said retainer supporting a plurality of independently rotatablebearing elements having simultaneous, preloaded pressure conmeans=fbrmedas a part'of one' of said members andprovidingfor-resiliently yieldablemovement thereof in response toabnormal pressures applied to saidbearing elements upon movement of the latter between portions of saidopposing surfaces which may be spaced more closely to-one another thanother portions of said surfaces.

7.;In a die set; the combination defined in claim 6, wherein said-pairofmembers comprise a post of polygonalacross-section and a tubular bushingof polygonal cross-section, and said last-named means comprises aplurality of longitudinal slots formed in said post and extending fromthe flat surfaces thereof a substantial distance inwardly of said post.

8; Ina die set, the combination defined in claim 6, whereinsaid'pair'of'members are'constituted by a bushingtandta post, andsaid lastanamedmeans comprises a longitudinal slot formed in said bushing and extendingfromone'side of said bushing a substantial distance inwardly thereof.

9.. A. die set comprising relatively reciprocable and interfitting. postand bushing members provided with opposing, relatively spaced,substantially parallel flat surfaces: defining therebetween a chamber ofpolygonal cross=sectional configuration; a bearing retainer conform-fiug-generally to the polygonal cross-sectional configuretion of saidchamber and positioned therein forlongitudinal reciprocating movement,said'retainer including a plurality of independently rotatablebearingelementshaw ing simultaneous, preloaded pressure contact with theopposing flat surfaces of said members, at least one of said membersbeing provided with longitudinally coextensive, resiliently yieldablesegments permitting limited displacement of the flat surfaces of saidmember in respouse to abnormal pressure applied to said bearing elementsupon movement of the latter between portions of the opposing-flatsurfaces of said members which may be spacedmore closely to one anotherthan other portions of said surfaces.

References Cited in the file of thispatent UNITED STATES PATENTS2,422,775 Conner June 24, 1947 2,61l',435 Jani'szewski Sept. 23, 1952FOREIGN PATENTS t -t 205,655 Great Britain Oct. 25,1923

